Re: ppp: frame with bad fcs
fairfax@pclink.com wrote:
> "...something munging bytes on the way through," is what I assume.
>
> I can load the same pages on my Win95 laptop with no problem with the same ISP, so it appears to be Linux somehow that is doing this.
>
> Last night I recompiled the kernel (a potato system, I had been using the default 2.2.14 kernel), and this seems to have relieved the problem somewhat -- stuff downloads very slowly from the problem sites, but I don't get the timeouts that I was getting. No error messages are now evident.
Maybe there aren't error messages but do an ifconfig on the interface and take a look at the error counts there. My guess is you're still getting the errors. You need to look closer at configuring your modem more likely than trying to do stuff with the software.
> Maybe I need to examine the packets that are getting sent over to me?
It would be good to know exactly what bytes are screwed up but this would be very difficult to ferret out. Probably not worth the time.
>
>
> > fcs is Frame Check Sequence. PPP over an async link uses HDLC-like framing for each packet. The FCS is used to detect errors in packets which are received. Such an
> > error could happen on a link which is not error-corrected. On a link which is error-corrected this probably indicates something is munging bytes on the way through.
> > This could happen because of things like software flow-control, which inserts XON/XOFF bytes into the stream to tell the other side to stop sending data. Make sure your
> > modem is configured to only do hardware flow control.
> >
> > fairfax@pclink.com wrote:
> >
> > > I am having trouble recieving files via PPP from certain sites. I checked the debugging log, and I am repeatedly getting a two-line error message from those sites:
> > >
> > > kernel: ppp: frame with bad fcs, length = 994
> > > kernel: ppp: bad frame, count = 994
> > >
> > > Can anyone tell me what this means?
> > >
> > > It seems that my PPP connection receives a bad frame, and keeps requesting that same frame over and over again (I get the same message repeated throughout the log).
> > >
> > > Thanks,
> > >
> > > Steve Martin
> >
> > --
> > Jens B. Jorgensen
> > jens.jorgensen@tallan.com
> >
> >
--
Jens B. Jorgensen
jens.jorgensen@tallan.com
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